Method of producing plastic cups



Feb. 4, 1947. l A. F. ITYQ` l 2,415,370

METHOD OF PRODUCING PLASTIC CUPS Filed Aug. 31, 1944 2 sheets-sheet 2 nh //////////////A Patented Feb. 4, 1947 2,415,370 v MErHoD oFPuonUcrNG PLASTIC ours Albert F. Pityo, Clifton, N. i.. Application August 31, 1944, Serial No. 552,060

9 Claims. l

I vide a method of the above mentioned character which employs a rigid member for exerting uniform pressure throughout the entire area of the periphery of the formed cup.

A further object of the invention is to provide a method which will produce a cup having increased strength at its bottom.

A further object of the invention is to provide a method for producing a bead upon the upper end of the cup.

Other objects and advantages of the invention will be apparent during the course of the following description:

In the accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same- Figure 1 is a plan View of a blank from which the cup is formed,

Figure 2 is a transverse section through the blank and forming plunger, with the clamping plunger about to clamp the blank to the forming plunger,

Figure 3 is a similar view, showing the blank clamped to the forming plunger and partly folded about the forming plunger,

Figure fi is a similar View showing the blank completely folded,

Figure 5 is a central vertical longitudinal section through the forming plunger and coasting mold,

Figure 6 is a similar view through the compression plunger and mold,

Figure l is a transverse section taken on line i-l of Figure 6,

Figure 8 is a perspective view of a completed cup,

Figure 8a is a fragmentary perspective view, upon an enlarged scale of the bead of the cup, andA Figure 9 is a transverse section taken on line 9 9 of Figure 8. f

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral Eil designates a blank, formed of absorbent fibrous material such as paper, cardboard, Woven fabric, such as cotton fabric. This blank is segmental and tapers'longi- (ci. 12s-sc) tudinally in one direction and is preferably scored or perforated along a longitudinal line Il. The line l I is longitudinally curved. At the line Il, the' blank is stamped' to provide tapered tongues i2, foldable upon' the line Ii and extending at a right angle thereto. The blank lil has an opposite Vlongitudinal end or edge i3 and is perforatedpro'rscored upon a longitudinal line Hl providing a.v bead forming zone i3. The scoring `line i4 7and edge i3 are longitudinally curved and arel laterally spaced and concentric. blank is provided at one tapered side with a 1ongitudinal tongue I5. This tongue terminates at -its oppositeends at the scored lines H and lll.

The zone i3 has end edges l5 and I5.

Priortothe stamping of the blank it, which may be formed of paper or other absorbent brous material, as stated, this blank is impregnated with'a liquid plastics material, by immersing the blank in such liquid plastics material. This plastics material is preferably a thermosetting plastics, dissolved in a suitable volatile solvent. I may use any of the thermo-setting phenolic plastics. As phenolic plastics, I may use phenol formaldehyde resin,'.urea formaldehyde resin or melamine formaldehyde resin. While it is preferred .to use a thermo-setting plastics material, lyet when the cup is not to be usedvfor holding hot liquids, a thermo-plastic material may be used. I may use styrene or styrol resin; or vinyl resin, as thermo plasticmaterials.

. The blank thus impregnated with the liquid plastics material is passed through a drier and is dried.

It is preferred to employ a continuous sheet of fibrous material, such as paper, and to feed the same longitudinally and stamp the blanks from thecontinuous sheet and leave the blanks connected so that they form a continuous strip. This continuous strip is immersed within and fed through .the plastics material liquid and is then passed through the drier.

The `blank il) is advanced to a position near and above a forming plunger i6, which is longitudinally tapered and circularly curved in cross section and has'a flat il. lThe blank i il is clamped .to the top of the horizontal then stationary form- .ing -lOlllIlger i6 by a clamping plunger I8, and the blank 'extends for equal distances upon opposite sides of the forming plunger i5. The blank thus held is now severed from the continuous strip of the blanks. The blank thus held is now'acted upon by vfolders i9, which move downwardly and also swing inwardly upon pivots 2i). These folders. frni -or fold the blank about the sides of the The forming plunger I E, the lower portions of the blank extending across the dat I'I and the longitudinal tongue I5 overlapping the adjacent side of the blank. The edge I5' abuts the edge I6 but these edges do not overlap. A holding or clamping lever 2I is now actuated to clamp the overlapping tongue and side of the blank together and to the flat I1, holding these parts against displacement. The clamping lever 2l may be pivoted at 22 and is operated by any suitable means and is axially movable with the forming plunger I6. The tapered tongues I2 are now folded laterally or inwardly upon the line I I and overlap to form the bottom of the cup, and may be held in the folded position by anysuitable means, if desired, but will ordinarily remain in approximately the folder position. The clamping lever 2 I while holding the overlapping portions of the blank is within the circumference of the plunger I6.

With the blank thus formed or folded and held upon the forming plunger i6, such plunger is moved axially into a mold 23, which is now stationary and has a cavity 24, which is longitudinally tapered and circularly curved in cross section, and has a longitudinal groove 25. This groove may be atthe top of the cavity and the top of the groove is circularly curved and concentric with the periphery of the cavity 24. The longitudinal groove 25 has a depth equal to the thickness of the blank, and a width equal to the width of the tongue I5. The mold 23 has a cylindrical cavity 26 at the large open end of the cavity 2t and having a larger diameter than the cavity 2G. The cavity 26 has a shoulder 26. A compressible block or cushion` 21 is arranged within the small end of the cavity 24 and may be formed of rubber. The rubber block 21 is carried by a plunger 21a. which is longitudinally adjustable and held stationary during the cornpression action. The mold has a jacket 28 for receiving steam to heat the mold.

The forming plunger I6 is rotated to bring the flat VI to the top position. The folders IS now release the blank while the clamping lever 2| continues to engage the same, and the forming plunger I6 is moved axially to enter the cavity 2d of the mold, The folded tongues I2 will engage the yielding block 21' and the longitudinal tongue I5, yis disposed upon the inner face of the overlapping side of the blank and in alignment with the groove 25. After the formed or folded blank has been properly introduced into the cavity 24, the clamping lever 2| is swung radially outwardly into the groove 25, to release its clamping engagement with the overlapipng yportions of the blank and the forming plunger is moved axially from Within the mold cavity 24 and the formed blank ls stripped from the forming plunger and remains within the mold cavity. The folded overlapping tongues now engage the block 2l while the tongue I5 overlaps the opposite side of the blank and is disposed inwardly of such side and in registration with the groove. The line i4 is arranged at the inner shoulder 26' of the cavity 2t while the edge I3 and zone I3 are within the cavity 26.

A rigid compression plunger 21 is employed, which is longitudinally tapered and circular in cross section, corresponding to the shapeI of the cavity 2 4, This plunger has a recess 28 formed in a cylindrical extension 28'. receiving a stiff spring 29, engaging a cross head 3ll,`secured to a bead forming plunger SI, slidable longitudinally upon the cylindrical extension 28'. The plunger 3l has a reduced cylindrical portion 33, provided with a rolling edge 34, to engage the edge I3 of the blank. The cylindrical extension 28 has a stop 35, slidable within aicavity 36, and arranged to engage a shoulder 3l. The spring 29 normally holds the plunger 3! rearwardly with respect to the cylindrical extension 23' so that shoulder 31 engages stop 35.

With parts thus adjusted, the cross head 3i! and plunger 2l are moved axially so that the plunger 2l enters the formed blank within the cavity 2li and forward pressure is applied to the cross head which is transmitted by the spring $3 to the plunger 2l until the cross head 3%! directly engages the cylindrical extension 2%', when such pressure is transmitted by the direct contact between the parts 3e and 28'. When the plunger 3l moves forwardly relative to the plunger E?, the reduced extension 33 engages the edge i3 and rolls the zone I3 to produce the bead les upon the cup i521. The plunger 2l presses the periphery or side portion of the cup against the side Wall of the cavity 2d, and Where the side of the blank overlaps the tongue i5, such side is forced into the groove 25. There are two layers of the blank at the groove 25 and since the groove has a depth equal to the thickness of Y the blank, the pressure upon the periphery oi the blank by the rigid plungel` 2l will be uniform throughout the entire area of such periphery or side. This enables me to employ a rigid compression plunger. The forward end Ia of the plunger presses the overlapping folded tongues l2 against the yielding block 2l', which will compensate for varying thicknesses at the bottom of the cup, caused by the overlapping tongues. The end 2lb is at. The formed blank is subjected to a pressure of substantially 200 pounds per square inch, for a period of from l5 seconds to seconds, while subjected to a temperature of 250 F. to 305 F. After this time interval the plastics material will set and the plunger 27 is moved axially from within the cavity 24. The completed cup may move out oi the cavity with the plunger 2 and be stripped from the plunger, or the cup may remain within the cavity when the plunger moves out of the cavity and be subsequently ejected from the cavity by moving the plunger 2la forwardly. The plunger 21e is stationary during the compression period, and may be lo-ngitudinally adjusted to regulate the degree of pressure applied to the bottom of the cup. This plunger is also moved to eject the cup, as stated. The blank IB is a single layer or uniform layer sheet, and the blank is folded to produce the side portion of the cup. This side portion is free from overlapping folds and therefore has the uniform or single layer formation of the blank, and a substantially uniform thickness. The overlapping tongue I5' and the opposite end of the blank form a multiple layer longitudinal zone having a greater thickness than the periphery or side portion. The longitudinal zone extends substantially from one end of the cup to the other end and the side portion extends continuously from one edge oi the longitudinal zone to the opposite edge of the longitudinal zone and also extends continuously substantially from one end of the cup to the oppositeend of the cup, terminating at the bead Ma at one end of the cup.

As shown in Figure 8. I have produced a completed cup formed oi paper impregnated with plastics material, and which is thin, light and strong. When a thermo-setting plastics material is used the cup' may be used for holding heated liquids. Due to the overlapping arrangement of the tongues i2, the bottom of the cup is reinforced and the cup is strongest 'at the bottom. The edges i5' and I6 of the formed bead abut and are joined together when the plastics material is treated and sets. This bead is continuous and has no rib which would be formed by the overlapping of the ends of the bead. The overlapping parts of the periphery of the cup form a slight exterior rib upon the cup. Instead of forming the groove 25 upon the Wall of the mold cavity 24 it could be formed in the compression plunger 2l, and this Would produce the rib upon the inner face of the periphery of the cup.

It is preferred to form the cup from paper impregnated with plastics material. Paper cannot be compressed and it is therefore impossible to exert a uniform pressure throughout the periphery of the paper blank by using a rigid compression plunger, where the periphery of the blank is formed of many overlapping portions, usually tapered. This is due to the extreme difficulty in determining the exact location, size, and thickness of overlapping portions, and producing accurately corresponding depressions in the periphery of the rigid compression plunger. Attempts have been made to overcome the difliculty by using a compressible plunger, formed of rubber, but such a plunger is not durable since there is necessarily some sliding action ybetween the plunger and the blank. action at the end 2lb of the plunger, I may use a rubber block 2l which will yield sufficiently to accommodate the varying thicknesses of the overlapping portions at the bottom of the cup and exert a uniform pressure upon the same.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same and that changes in the order of the steps of the method may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention What I claim is:

l. The method of producing a tapered cup or the like to hold hot material, comprising Inaking a blank having opposed edges from a uniform layer sheet of fibrous absorbent material impregnated with a thermo-setting plastics mate rial, forming the blank by overlapping its opposed edges to provide a tapered tube having a mutiple layer longitudinal zone and side portion free from overlapping folds and thereby having the uniform layer formation of the blank and a substantially uniform thickness, the side portion extending continuously from one edge of the longitudinal zone to the opposite edge of the zone and also extending substantially from one end of the cup to the opposite end of the cup, introducing the tapered tube into the tapered cavity of a rigid mold having a longitudinal groove which leads into the mold cavity and has the same length and width as the longitudinal zone and a depth equal to the thickness of the side portion, arranging the longitudinal zone in registration with the longitudinal groove, subjecting the uniform layer side portion and longitudinal zone to the action of rigid pressure from a rigid plunger arranged lwithin the tube which pressure i sfsubstantially uniform throughout the side porvtion and longitudinal zone by causing the longitudinal zone to be compressed Within the groove,

Since there is no sliding heating the tapered tube while subjected to such pressure to cure the same, and removing the tapered tube from the mold cavity.

2. rlhe method of producing a tapered cup or the like adapted to hold hot material, comprising making a blank having opposed edges from a uniform layer sheet of paper impregnated with a thermo-setting plastics material, forming the blank by overlapping its opposed edges to provide a tapered tube having a multiple layer longitudinal zone and side portion free from overlapping folds and thereby having the uniform layer formation of the blank and a substantially uniform thickness, the side portion extending continuously from one edge of the longitudinal zone to the opposite edge of the zone and also extending substantially from one end of the cup to the opposite end of the cup, introducing the tapered tube into the tapered cavity of a rigid mold having a longitudinal groove which leads into the mold cavity and has the same length and width as the longitudinal zone and a depth equal to the thickness of the side portion, arranging the longitudinal zone in registration with the longitudinal groove and introducing a tapered rigid plunger into the tapered tube, moving the tapered rigid plunger axially with respect to the mold for subjecting the uniform layer side portion and longitudinal zone to the action of rigid pressure from the rigid plunger which is substantially uniform throughout the side portion and longitudinal Zone by causing the longitudinal zone to be compressed within the groove, heating the tapered tube While subjected to such pressure to cure the same, and removing the tapered tube from the mold.

3. The method of producing a tapered cup or the like to hold hot materials, comprising making a blank having opposed edges from a sheet of paper impregnated with a thermo-setting plastics material and having a substantially uniform thickness throughout, forming the blank by overlapping its opposed edges to provide a tapered tube having a multiple layer 1ongitudinal zone and side portions free from overlapping folds and thereby having the substantially uniform thickness of the blank, the longitudinal zone having twice the thickness of the side portion, the side portion extending continuously from one edge of the longitudinal Zone to the opposite edge of the longitudinal Zone and also extending substantially from one endl of the cup to the opposite end of the cup, introducing the tapered tube into the tapered cavity of a rigid mold member, introducing a tapered rigid plunger member into the tapered tube, one of said members being provided with a longitudinal groove which leads into the mold cavity and has rigid Walls and has the same length and Width as the longitudinal Zone and a depth equal to the thickness of the side portion, arranging the longitudinal zone in registration with said groove, moving the tapered plunger member axially with respect to the moid member for subjecting the side portion and longitudinal zone to the action of rigid pressure from the rigid plunger member which is substantially uniform throughout the side portion and longitudinal lzone and causing the longitudinal zone to be compressed within the groove, heating the tapered tube while it is subjected to pressureto cure the same, and removing the tapered tube from the mold cavity.

4. The method of producing a tapered cup or the like to hold hot materials, comprising making a blank having opposed edges from a sheet of paper having a substantially uniform thickness throughout and impregnated with a thermo-setting plastics material, forming the blank by overlapping its opposed edges to provide a tapered tube having a multiple layer longitudinal zone and side portions free from overlapping folds and thereby having the uniform thickness of the blank, the side portion extending continuously from one edge of the longitudinal zone to the opposite edge of the zone and also extending sub stantially from one end ci the cup to the opposite end of the cup, introducing the tapered tube into the tapered cavity of a rigid mold member, introducing a tapered rigid plunger member into the tapered tube, one of said members being provided with a longitudinal groove which leads into the mold cavity and has rigid walls and has the same length and width as the longitudinal groove l and a depth equal to the thickness of one of the overlapped edges, arranging the longitudinal zone in registration with said groove, moving the tapered plunger member axially with respect to the mold member for subjecting the side portion and longitudinal zone to the action of rigid pressure from the rigid plunger member which is substantially uniform throughout the side portion and longitudinal zone and causing the longitudinal zone to be compressed Within the groove, heating the tapered tube While it is subjected to pressure to cure the same, and removing the tapered tube from the mold cavity.

5. The method of producing a tapered cup or the like adapted to hold hot material, comprising introducing into the tapered cavity of a, rigid mold having a longitudinal groove having the same length and width as the longitudinal Zone of a tube to be formed a depth equal to the thickness ofthe body portion of such tube, a tapered tube embodying a blank having opposed edges and formed of dried fibrous material impregnated with a thermo-setting plastics material, the opposed edges being overlapped for `forming a multiple layer longitudinal zone and a side portion of substantially the same thickness throughout, the Zone having a greater thickness than the side port-ion, the side portion extending continuously from one edge of the longitudinal zone to the opposite edge of the Zone and also eX- tending substantially from one end of the cup to the opposite end of the cup, arranging the longitudinal zone in registration With the longitudinal groove, moving a tapered plunger axially with respect to the mold for subjecting the side portion and longitudinal zone to the action of rigid pressure fromthe rigid mold which is substantially uniform throughout the side portion and longitudinal Zone by causing the longitudinal zone to be compressed Within the groove, heating the tapered tube While subjected to such pressure to cure the same, and removing the tapered tube from the mold cavity.

6. The method of producing a tapered cup or the like adapted to hold hot material, comprising introducing into the tapered cavity of a rigid mold having a longitudinal groove, a tapered tube embodying a blank having opposed edges and :formed `from paper impregnated with a thermo-setting plastics material, the opposed edges being overlapped for forming g multiple layer longitudinal zone and a side portion of substantially the same thickness throughout, the sideportion extending continuously from one edge of the longitudinal zone to the opposite edge of the zone and also extending substantially from one end of the cup to theV opposite end of the cup, the longitudinal groove having the same Width and length as the longitudinal zone and a depth equal to the thickness of one of the overlapped edges, arranging the zone in registration with the groove, introducing a tapered rigid plunger into the tapered tube, moving the tapered plunger axially with respect to the mold for subjecting the side portion and longitudinal zone to the action of rigid pressure from the rigid mold which is substantially uniform throughout the side portion and longitudinal zone by causing the longitudinal zone to be compressed Within the groove, heating the tapered tube while subjected to such pressure to cure the same, and removing the cured tapered tube from the mold.

7. The method of producing a tapered cup or the like adapted to hold hot material, comprisinLT making a blank from a dried paper sheet impregnated with a thermo-setting plastics material and making the blank with converging opposed edges and opposed curved edges and a plurality of tongues at one curved edge, forming the blank by overlapping its opposed converging edges to provide a tapered tube having a multiple layer longitudinal Zone and side portion free from overlapping folds and having a substantially uniform thickness, the side portion extending continuously from one edge of the longitudonal zone to the opposite edge of the longitudinal zone, folding the tongues inwardly in overlapping relation to provide a bottom having portions of varying thicknesses, introducing the tapered tube into the tapered cavity of a rigid mold, having a longitudinal groove having the same length and Width as the longitudinal Zone and a depth equal to the thickness of one of the overlapping edges, arranging the longitudinal zone in registration with the longitudinal groove, introducing a tapered rigid plunger into the tapered tube, moving the tapered plunger axially within the mold for subjecting the side portion and longitudinal Zone to the action of rigid pressure from the rigid plunger which is substantially uniform throughout the side portion and longitudinal Zone by causing the longitudinal Zone to move into the groove, subjecting the overlapping tongues to pressure from the end of the plunger while yieldingly opposing such pressure from the opposite sides of the tongue, heating the tapered tube While subjected to pressure, and removing the tube from the mold cavity.

8. The method of producing a cup or the like adapted to hold hot material, comprising making a blank from a uniform layer sheet of dried fibrous absorbent material impregnated With a thermo-setting plastics material and providing the blank with opposed edges and a curved edge between the opposed edges and having a notch at one end, forming the blank by overlapping its opposed edges to provide a tube having a multiple layer longitudinal zone and side portion free from overlapping folds and thereby retaining the uniform layer formation of the blank and having a substantially uniform thickness,

the side portion extending continuously from one edge of the longitudinal Zone to the opposite edge of the zone and also extending substantiallyY from one end of the cup to the opposite end the cup, introducing the tube into the cavity of a rigid mold having a longitudinal groove in its side which has the same Width and length as the longitudinal zone and a depth equal to the thickness of the side portion and an enlarged,

recess at one end and arranging the longitudinal zone in registration with the longitudinal groove and the curved edge Within the enlarged recess, introducing a rigid plunger in the tube, subjecting the uniform layer side portion and longitudinal zone to the action of rigid pressure from the rigid plunger which is substantially uniform throughout the side portion and longitudinal zone by causing the longitudinal zone to be compressed within the groove, subjecting the curved edge within the enlarged recess to a rolling and pressing action, heating the tube While subjected to such pressure, and then removing the tube from the mold cavity.

9. The method of producing a, cup or the like for holding hot material, comprising making a blank having opposed edges from a uniform layer sheet of dried fibrous absorbent material impregnated with a thermo-setting plastics material, forming the blank upona folding plungerby overlapping its opposed edges to provide a tube having a, multiple layer longitudinal Zone and side portion free from overlapping folds and thereby having the uniform layer formation of the blank and a substantially uniform thickness, the side portion extending continuously from one edge of the longitudinal Zone to the opposite edge of the zone and also extending substantially from one end of the cup to the opposite end of the cup, clamping the opposed overlapping edge portions against the folding plunger by means of a longitudinal member arranged substantially Within the circumference of the folding plunger, introducing the folding plunger and tube and longii0 tudinal clamping member into the cavity of a rigid mold having a longitudinal groove and arranging the clamping member in alignment with the groove, moving the clamping member into the longitudinal groove for releasing the tube and withdrawing the folding plunger and clamping member from the mold cavity, introducing a rigid plunger into the tube held Within the mold cavity, subjecting the uniform layer side portion and longitudinal zone to the action of rigid pressure from the rigid plunger Which is substantially uniform throughout the side portion and longitudinal zone by causing the longitudinal zone to move into the groove, heating the tube While subjected to such pressure to cure the same, and removing the tube from the mold cavity.

ALBERT F. PITYO.

REFERENCES CITED The following references are oi record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 2,337,581 'Wiley Dec. 28, 1943 2,348,871 Wiley May 16, 1944 1,640,543 Grudge Aug. 30, 1927 1,189,822 House July 4, 1916 1,802,101 'Wood Apr. 21, 1931 1,570,128 Carter Jan. 19, 1926 1,501,026 Guay July 8, 1924 1,189,822 House July 4, 1916 

